9000 BTU A/C vs 12000 BTU

[bobdelso]

I want to run an A/C off my 1200 watt solar setup with 560 ah of batteries.

A 9000 btu 17 seer mini split a/c unit will use around 650-750 and up to 900 watts
A 12000 btu mini split uses an average of 900 with up to 1100.

If they are both inverter mini splits, wouldn't they use the same amount of power if set at the same temperature? The 12k one would be running slower but using the same watts.

Is my thinking off?

 

[robby]

No they would not use the same amount of power because the 12000 has a bigger compressor.
Even though you set them to the same temp they will both start out slow but in a minute or so ramp up to full power until the room starts to get down near to the set temperature and then slow down. When the set temperature is reached they will both be using a lot less power as the motors are running a lot slower. The full power level is going to be your major hurdle for that inverter.

It is also likely that the smaller one will be ramping up much more frequently to keep the room cool versus the bigger one. It all depends on if they are sized right for the room and also how well the room is insulated plus how often the room door is opened. I personally always go one size larger than what is required, but that was before I got into solar.